The present invention relates to a linear guide/feed module having a tubular boom that can be moved along a movement axis, having a housing that encompasses the tubular boom, which housing the boom can travel out of and into along the movement axis, and having a drive unit that drives the boom to move in relation to the housing; for its movement along the movement axis relative to the housing, the boom is supported in the housing by means of at least two recirculating rolling element rows that are spaced apart from each other in the circumference direction around the movement axis; each of these recirculating rolling element rows has a force-loaded rolling element carrying segment extending essentially in the direction of the movement axis and an essentially unloaded rolling element return segment.
The present invention also relates to a boom for such a linear guide/feed module and a method for manufacturing it.
A species-defining feed module with a linear guide is known, for example, from DE 87 12 696 U1 or from EP 0 907 456 B1.
DE 87 12 696 U1 has disclosed a linear guide/feed module having a tubular housing into which a boom is coaxially inserted in such a way that it can move in relation to the housing. A threaded spindle drives the boom to travel into and out of the housing in the direction of the movement axis. Hollow cylindrical shell segments are mounted in the housing by means of positioning pins and screws. Radially extending support surfaces of the hollow cylindrical shell segments have roller recirculation shoes attached to them, each of which contains a recirculating rolling element row.
On the side of the boom oriented away from the hollow cylindrical segment, the boom is supported on these roller recirculation shoes with corresponding support surfaces that likewise extend in the radial direction.
EP 0 907 456 B1 has also disclosed a linear guide/feed module that can be viewed as species-defining. The feed module known from this patent application has a boom and a coaxial housing encompassing the boom. Prefabricated recirculating ball units with two carrying segments each are inserted into recesses in the housing and screw-mounted there in the same way as the roller recirculation shoes in the above-mentioned DE 87 12 696 U1. With reference to the housing center axis that coincides with the movement axis, the recirculating ball units protrude radially from the housing into the cavity that contains the boom. There are four recirculating ball units offset from one another by a 90° angle in the circumference direction. The boom is guided on the carrying segments of these recirculating ball units so that it can move in relation to the housing in the direction of the movement axis.
A disadvantage of the linear guide/feed modules mentioned above is the high cost of assembly required to achieve a precise alignment of the individual recirculating ball units and roller recirculation shoes. These prefabricated recirculating units must be adjusted both in terms of how parallel they are to the desired movement axis and in terms of the degree to which they exert a preloading force on the boom.
As further prior art, reference is also made to EP 0 767 526 B1, which has disclosed a linear guide/feed module in which the boom is guided so that it can move in the direction of the movement axis inside the housing encompassing it by means of a slideway instead of a rolling element guide. The slideway between the housing and boom is embodied according to EP 0 767 526 B1 in the form of a wedge profile in order to simultaneously prevent the boom from rotating in relation to the housing. A disadvantage of this design, though, is the powerful forces required to move the boom in relation to the housing due to the presence of the slideway.
As further prior art, reference is also made to the patent application U.S. Pat. No. 6,700,228 B2, which has disclosed a linearly guided carriage driven by a linear motor. This carriage is supported so that it can move in the guidance direction by means of recirculating rolling element rows situated on opposite side walls in a U-shaped carrier.
Finally, reference is made to patent application CH-A-315948, which has disclosed a peening discussed below as a method for manufacturing tubes with a desired inner contour that deviates from a smooth cylindrical form, e.g. barrel.